﻿/*******************************************************************************
 * Copyright (c) 2007
 * Sergey Berezin, Dmitry Voitsekhovskiy
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms,
 * with or without modification, are permitted provided
 * that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * - Neither the name of the Moscow State University nor the names
 * of its contributors may be used to endorse or promote products
 * derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ******************************************************************************/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Linq.Expressions;

namespace Faml.LinqCompiler
{
    public static class ExpressionUtils
    {
        public static IEnumerable<Expression> GetChildren(Expression exp)
        {
            if (exp is LambdaExpression)
            {
                LambdaExpression lexp = (LambdaExpression)exp;
                foreach (ParameterExpression param in lexp.Parameters)
                {
                    yield return param;
                }
                yield return lexp.Body;
            }
            else if (exp is MethodCallExpression)
            {
                MethodCallExpression mce = (MethodCallExpression)exp;

                foreach (Expression arg in mce.Arguments)
                {
                    yield return arg;
                }
            }
            else if (exp is MemberExpression)
            {
                MemberExpression me = (MemberExpression)exp;
                yield return me.Expression;
            }
            else if (exp is UnaryExpression)
            {
                UnaryExpression ue = (UnaryExpression)exp;
                yield return ue.Operand; 
            }
            else if (exp is BinaryExpression)
            {
                BinaryExpression be = (BinaryExpression)exp;

                yield return be.Left;
                yield return be.Right;
            }
            else if (exp is InvocationExpression)
            {
                InvocationExpression ie = (InvocationExpression)exp;

                yield return ie.Expression;

                foreach (Expression arg in ie.Arguments)
                {
                    yield return arg;
                }
            }
            else if (exp is NewArrayExpression)
            {
                NewArrayExpression nae = (NewArrayExpression)exp;

                foreach (Expression e in nae.Expressions)
                {
                    yield return e;
                }
            }

            yield break;
        }
    }
}
